A double-flow turbine engine generally comprises an air intake system for supplying air to the systems using air within the aircraft such as, for example, the air pressure renewal and control system in the cabin or, in turn, the defrosting systems. The air intake system draws off hot air at the hot sections of the turbine engine and cold air at the fan duct of said turbine engine. So that the temperature of the air supplied to the aircraft air systems remains lower than a limit temperature, the air intake system comprises an exchanger (PCE) in which the cold and hot air flows are mixed. The cold air is fed to the exchanger via an air passage which connects the exchanger to the fan duct in a fluidic manner. The passage comprises an air inlet opening with a scoop-type operation at its upstream end. This inlet opening is flush with the fan duct wall, in order to reduce its aerodynamic impact, namely its drag. However, with this kind of geometry, an inlet opening cannot capture a sufficient flow of cold air for all applications of the air intake system of a turbine engine with a high bypass ratio (greater than 13:1) in which the temperature of the hot air drawn off can exceed 550° C. (as compared with 450 to 500° C. for other turbine engines). This occurs in particular in extreme operating states of the air intake system, in other words, when the demand of the air-usage systems is high and is combined with a low engine speed.
A solution adapted to turbine engines of this kind to cover all applications of the air intake system would be to arrange a large-sized air inlet opening extending largely within the fan duct and combined with an exchanger with a large exchange surface. This solution is not feasible on account of the limited space available in the turbine engine.